From the street, a garden shed, a backyard studio and a granny flat can look much the same. What separates them is how they are used. Use decides the building's class under the National Construction Code (NCC), and the class decides which building rules and approval pathways apply.
Building classes in brief
The NCC sorts buildings into classes. The ones that matter for backyard buildings are:
- Class 10a: buildings nobody lives in, for example a private garage, carport or shed.
- Class 1a: a house, including a granny flat or other self-contained home.
- Class 7b: a building used for storage, such as a warehouse.
- Class 8: a building used for production or repairs, such as a factory or commercial workshop.
The ABCB states plainly that a habitable building, such as a sleepout, can't be classed as Class 10. If people sleep, live or work in it, it is not a shed in code terms. Where one building has more than one use, the stricter class requirements generally apply.
How each use is approved
Storage shed or garage. A small domestic shed may be exempt development if it meets the Codes SEPP limits. Larger sheds usually need a complying development certificate (CDC) or a development application (DA). See Shed size limits for building without approval in NSW.
Studio, home office or rumpus room. A space used for hobbies, study or work by the household is habitable. It must meet rules for ceiling height, light, ventilation, insulation and weatherproofing, like any room in a house. The Housing Code allows a detached studio, which supports life in the main house and is not a separate home. Our backyard studios page covers this path.
Granny flat. Once the building is a self-contained home, with a kitchen and bathroom of its own, it is a secondary dwelling. Different planning rules apply, including size and lot limits. See our granny flats page.
Business use. Running a business from an outbuilding can bring in planning rules for home businesses and home industries. If the use goes beyond what those rules allow, the building may become a Class 7b or Class 8 building. CertifiBuild does not certify Class 2 to 9 buildings. Work in those classes needs a certifier with the right registration.
Why the label on the plans matters
A shed approved as Class 10a was designed for storage. It may have a low ceiling, no insulation, no damp-proofing and no smoke alarm. Using it as a bedroom later puts people at risk and leaves the building unapproved for that use.
This comes up in a few common ways:
- A shed fitted out as a bedroom for a teenager or guest.
- A workshop with a toilet and kitchenette that becomes a home.
- A detached garage converted into a home office. See our article on Garage to habitable room: what changes in a conversion.
- A storage shed later rented out to a small business.
In each case the building takes on a new use, and that use needs approval. Without it, there can be problems with insurance, council orders, or a buyer's solicitor at sale time. A building information certificate is often the way to regularise work already done.
Plan for the use you actually want
If there is any chance the building will be lived or worked in, design it as habitable from the start. Getting the ceiling height, windows, insulation and slab detail right at the start costs much less than retrofitting them. Write the planned use clearly on each drawing, which lets the certifier apply the correct class.
Engineering also follows the use and design. A kit shed's engineering is set for a storage building. See Kit sheds: engineering, wind ratings and certification for what that covers.
CertifiBuild certifies Class 1 and Class 10 buildings across NSW. Learn more on our sheds and outbuildings service, or request a quote and tell us how you plan to use the building.
Local help across NSW
CertifiBuild certifies Class 1 and Class 10 work in 39 council areas. Local rules on these council pages are a good place to start: Camden Council, Burwood Council, Woollahra Municipal Council, Hornsby Shire Council, Liverpool City Council, Lithgow City Council.
Suburb pages with local planning notes: Cobbitty, Croydon, Edgecliff, Glenhaven, Greendale, Hartley, Homebush, Lidsdale, Littleton, Luddenham. You can also browse every service area.
Sources
- Part A6 building classification, NCC 2022 Volume Two (ABCB)
- Fact sheet on exempt garden sheds, cubby houses and similar structures, NSW Department of Planning
- State Environmental Planning Policy (Exempt and Complying Development Codes) 2008, NSW Legislation